Bobbin for reciprocating motor and fabrication method thereof

ABSTRACT

A bobbin for a reciprocating motor and fabricating method thereof includes the bobbin comprising a bobbin body ( 310 ) including a first sidewall unit ( 312 ) and a second sidewall unit ( 313 ) forming a certain space in the body by extending at a certain height so as to have slopped part from both side of the bottom ( 311 ) having a ring form with a certain width; a winding coil ( 320 ) wound a plurality of times in the space of inner side of the bobbin body; ( 310 ) and a cover ( 330 ) couple to the bobbin body ( 310 ) so as to cover the winding coil ( 320 ), and a molding step for fabricating the bobbin, thereby fabrication of the winding coil and laminated outer core constituting the motor is simplified, the length of the permanent magnet constituting the mover can be shortened. So, fabricating cost of the motor can be reduced and mass productivity of the motor can be improved.

This application is the national phase under 35 U.S.C. § 371 of PCTInternational Application No. PCT/KR01/00880 which has an Internationalfiling date of May 25, 2001, which designated the United States ofAmerica.

TECHNICAL FIELD

The present invention relates to a bobbin of a reciprocating motor, andmore particularly, to an improved bobbin of a reciprocating motor thatis capable of reducing an amount of a permanent magnet to be used forconstituting a reciprocating motor which generates a linear reciprocaldriving force and suitable to a mass-production of a motor, and afabrication method thereof.

BACKGROUND ART

In general, a motor is an instrument for converting an electric energyto a kinetic energy. There are two types of motors: one is a rotarymotor which converts the electric energy to a rotational movement, andthe other is a reciprocating motor which converts the electric energy toa linear reciprocal movement.

As a driving source, the motor is adopted for use to various fields.Especially, it is installed in almost every home appliance such as arefrigerator, an air-conditioner, a washing machine or an electric fan.

In case of the refrigerator and the air-conditioner, the motor is notonly used to rotate a ventilating fan but also installed as a drivingsource at a compressor of a cooling cycle apparatus of the refrigeratorand the air-conditioner.

FIG. 1 is an example of a general reciprocating motor in accordance witha conventional art.

As shown in FIG. 1, the reciprocating motor includes a stator having acylindrical outer core 10 and an inner core 20 inserted into the outercore 10 with a predetermined space, a winding coil 30 combined to theouter core 10 or the inner core 20, and a mover 40 inserted linearlymovable between the outer core 10 and the inner core 20.

FIG. 1 shows the structure in which the winding coil 30 is combined withthe outer core 10.

The outer core 10 is formed as a cylindrical stacked body in whichchannel-shaped thin lamination sheets 11 are stacked radially to make acylindrical form.

The channel portion of the lamination sheet 11 makes a pass part 11 awhere a flux flows, and both ends make pole parts 11 b where a pole isformed. The space with one side opened formed inside the pass part 11 amakes an opening 11 c in which the winding coil 30 is positioned.

Referring to the winding coil 30, a coil is wound for a plurality oftimes to form a ring shape, a section form of which is equivalent to theform of the opening 11 c.

A thin insulation coating film 31 is formed on the outer surface of thewinding coil 30.

The inner core 20 is formed as a cylindrical stacked body that a thinrectangular lamination sheet 21 having a length equivalent to the lengthof the outer core 10 is stacked radially to make a cylindrical form.

The mover 40 includes a cylindrical magnet holder 41 inserted betweenthe outer core 10 and the inner core 20 and a plurality of permanentmagnets 2 fixedly combined to the outer circumferential surface of themagnet holder 41.

The length Lp of the permanent magnet 42 is usually equivalent to thesum of the length Lp of the pole part and the interpole distance Lb.Accordingly, since the length of the permanent magnet 42 is inproportion to the interpole distance Lb positioned at both sides of theopening 11 c, the shorter the interpole distance Lb is, the shorter Lmof the permanent magnet 42 becomes.

The length Lp of the pole part corresponds to the stroke, and theinterpole distance Lb is equivalent to the width of the entrance of theopening 11 c.

As for the combination between the winding coil 30 and the outer coil10, the insulation coating film 31 is coated at the outer side of thewinding coil 30 formed as a coil is wound in a ring-shape for many oftimes, and the lamination sheets 11 constituting the outer core 10 arestacked to be combined radially at the winding coil 30.

The lamination sheets 11 are stacked such that the winding coil 30 isinserted into the opening 11 c.

The operation of the reciprocating motor constructed as described abovewill now be explained with reference to FIG. 2.

As shown in FIG. 2, when a current flows to the winding coil 30, a fluxis generated around the winding coil 30 due to the current flowing alongthe winding coil 30. The flux flows to form a closed loop along the passpart 11 a of the outer core and the inner core 20 which constitute thestator (S).

The interaction between the flux according to the current flowing alongthe coil 30 and the flux according to the permanent magnet 42constructing the mover 40 makes the permanent magnet 42 to move in theaxial direction.

When the direction of the current flowing to the winding coil 30 ischanged, the direction of the flux formed at the pass part 12 of theouter core and the inner core 20 is accordingly changed, and thus, thepermanent magnet 42 is moved in the opposite direction.

When the current is supplied to the permanent magnet 42 by changing itsdirection by turns, the permanent magnet 42 is moved linearly andreciprocally between the outer core 10 and the inner core 20.Accordingly, the mover 40 has a linear reciprocal driving force.

However, the reciprocating motor having the above described constructionhas many problems.

For example, first, since the width of the entrance of the opening 11 cwhere the winding coil 30 is positioned, that is, the interpole distanceLb, is great, causing that the size of the high-priced permanent magnet42 which is determined depending on the interpole distance Lb islengthened. Thus, as the amount of the permanent magnet 42 to be used isincreased, a high production cost is incurred which is not suitable to amass-production.

Secondly, since the outer core 10 is constructed by stacking theplurality of lamination sheets 11 at the winding coil 30 after thewinding coil 30, which is formed by winding the coil having apredetermined length many times, is coated for insulation, it is noteasy to fabricate the winding coil 30 in conformity to the form of theopening 11 c of the outer core 10.

In addition, since the winding coil 30 is easily deformed, making itdifficult to stack the lamination sheets 11, the fabrication time ismuch taken and more processes are required, and thus, it is not suitableto a mass-production.

DISCLOSURE OF THE INVENTION

Therefore, it is an object of the present invention to provide a bobbinof a reciprocating motor that is capable of reducing an amount of apermanent magnet to be used for a reciprocating motor which generates alinear reciprocal driving force and suitable to a mass-production, andits fabrication method.

To achieve these objects, there is provided a bobbin of a reciprocatingmotor including: a bobbin body having a first side wall part and asecond side wall part which are respectively extended to a predeterminedheight to have a tilt portion at both sides of a ring-shaped bottom of apredetermined width to thereby form a predetermined space therein; awinding coil formed by winding a coil for several times at a spaceformed inside the bobbin body; and a cover combined with the bobbin bodyto cover the winding coil.

To achieve the above objects, there is also provided a method forfabricating a bobbin of a reciprocating motor including the steps of:first-molding the bobbin body having the first side wall part and thesecond side wall part which form a predetermined space therein by beingextended to a predetermined height to have a tilt portion at both sidesof the ring-shaped bottom of a predetermined width; fabricating awinding coil by winding a coil for plural times at the space formedinside the bobbin body; and second-molding the cover combined with thebobbin body to cover the winding coil.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a front-sectional view of a general reciprocating motor inaccordance with a conventional art;

FIG. 2 is a front-sectional view illustrating an operational state ofthe reciprocating motor in accordance with the conventional art;

FIG. 3 is a front-sectional view of a reciprocating motor with a bobbinin accordance with a preferred embodiment of the present invention;

FIG. 4 is a front-sectional view of a bobbin of a reciprocating motor inaccordance with the preferred embodiment of the present invention;

FIGS. 5 and 6 are front-sectional views illustrating modifications ofthe bobbin of a reciprocating motor in accordance with the preferredembodiment of the present invention;

FIG. 7 is a sectional view illustrating a protrusive louver of thebobbin of a reciprocating motor in accordance with the preferredembodiment of the present invention; and

FIG. 8 is a flow chart of a method for fabricating the bobbin of areciprocating motor in accordance with the preferred embodiment of thepresent invention.

MODES FOR CARRYING OUT THE PREFERRED EMBODIMENTS

A bobbin of a reciprocating motor and its fabrication method inaccordance with a preferred embodiment of the present invention will nowbe described with reference to the accompanying drawings.

FIG. 3 is a front-sectional view of a reciprocating motor with a bobbinin accordance with a preferred embodiment of the present invention.

As shown in FIG. 3, a cylindrical inner core 200 is combined inside thecylindrical outer core 100 with a predetermined interval. The outer core100 and the inner core 200 constitute a stator (S).

A bobbin 300 is combined with the outer core 100 of the stator. Thebobbin 300 may be combined with the inner core 200.

A mover 400 is inserted to be linearly movable between the outer core100 and the inner core 200.

The mover 400 includes a cylindrical magnet holder 410 inserted betweenthe outer core 100 and the inner core 200 and a plurality of permanentmagnets 420 combined at the outer circumferential surface of the magnetholder 410.

With reference to FIG. 4, the bobbin 300 includes: a bobbin body havinga first side wall part 312 and a second side wall part 313 which arerespectively extended to a predetermined height to have a tilt portionat both sides of a ring-shaped bottom 311 of a predetermined width tothereby form a predetermined space therein; a winding coil 320 formed bywinding a coil for several times at a space formed inside the bobbinbody 310; and a cover 330 combined with the bobbin body to cover thewinding coil.

A first combining part 314 is formed at both end faces of the first sidewall part 312 and the second side wall part 313 of the bobbin body 310,and a second combining part 331 is provided to be combined with thefirst combining part 314 at the inner face of the cover 330.

The first combining part 314 and the second combining part 331 areformed to be concavo-convex for mutual combination. That is, the firstcombining part 314 is formed by having a recess having a predeterminedwidth and depth at the end faces of the first side wall part 312 and thesecond side wall part 313, and the second combining part 331 has aprotrusion having a predetermined width and length corresponding to theform of the recess at both sides of the cover 330.

Or, reversely, the first combining 314 may be formed having a protrusionwith a predetermined width and height at the end faces of the first sidewall part 312 and the second side wall part 313 while the secondcombining part 331 may include a recess having a predetermined width anddepth corresponding to the form of the protrusion at both sides of thecover 330.

The protrusion and the recess to be combined with the protrusion may beformed by plural ones.

The first side wall part 312 includes a first slant wall 315 extendedlyformed to having a predetermined slope angle to a bottom part 311 at oneside of the bottom part 311, and a first vertical wall 316 extendedlyformed from the first slant wall 315 in the vertical direction to thebottom part 311.

The first slant wall 315 has a predetermined thickness and is slantedoutwardly of the bottom part 311. That is, it makes an obtuse angle tothe bottom part 311.

The second side wall part 313 includes a second slant wall 317extendedly formed to having a predetermined slope angle to the bottompart 311 at the other side of the bottom part 311, and a second verticalwall 318 extendedly formed from the second slant wall 317 in thevertical direction to the bottom part 311.

The second slant wall 317 has a predetermined thickness and is formedslant to make an obtuse angle to the bottom part 311 outwardly of thebottom part 311.

It is preferred that the first slant wall 315 and the second slant wall317 have the same slope angle and the first vertical wall 316 and thesecond vertical wall 318 are formed in parallel.

A plurality of step faces (F) are formed at the inner faces of the firstslant wall 315 and the second slant wall 317.

It is preferred that the step faces (F) have a stairway form, and thestep face (F) formed at the first slant wall 315 and the step face (F)formed at the second slant wall 317 have different heights to eachother.

FIG. 5 is a modification of the first slant wall 315 and the secondslant wall 317.

As shown in FIG. 5, the first slant wall 315 and the second slant wall317 are formed to have a predetermined thickness, respectively.

FIG. 6 is a modification of the first side wall part 312 and the secondside wall part 313.

As shown in FIG. 6, the first side wall part 312 includes a first slantstep wall 341 formed in a stairway form and having a predeterminedthickness at one side of the bottom part 311 and a first vertical wall316 extendedly formed from the first slant step wall 341 in the verticaldirection to the bottom part 311.

The second side wall part 313 includes a second slant step wall 342formed in a stairway form and having a predetermined thickness at oneside of the bottom part 311 and a second vertical wall 318 extendedlyformed from the first slant step wall 342 in the vertical direction tothe bottom part 311.

It is preferred that the levels of the first slant step wall 341 andthose of the second slant step wall 342 are different.

With reference to FIG. 7, a protrusive louver 319 is formed at the wholeor a partial outer face of the first wide wall 312 and the second sidewall part 313, so as to be closely adhered to a motor core when combinedwith the motor core.

The winding coil 320 is formed by winding a coil for many times insidethe bobbin body 310.

The coil starts winding in zigzag, in the longitudinal direction of thebottom part 311, from the corner where the bottom part 311 and the firstside wall part 312 meet or the corner where the bottom part 311 and thesecond side wall part 312 meet. In this respect, the coil ishorizontally arranged to be wound in the longitudinal direction by thestep faces (F) formed at the first slant wall 315 and the second slantwall 317.

The winding coil is positioned at the internal space formed by thebottom part 311 of the bobbin body 310 and the first and the second sidewall parts 312 and 313.

It is preferred that the bobbin body 310 and the cover 330 areintegrally shaped by molding.

The outer core 100 is formed such that lamination sheets 100 consistingof an ‘L’-shaped pass part 111 and an extended part 112 extended in atriangle form at an inner side of one end of the pass part 111 areradially stacked to make a cylindrical form in the bobbin 300.

One lamination sheet 110 is radially stacked such that the extended part112 contacts with the first slant wall 315 of the first side wall partof the bobbin 300 and the pass part 111 contacts with the outer faces ofthe first vertical wall 316 of the first side wall part and the cover ofthe bobbin 300, and a different lamination sheet 110 is radially stackedto be contacted with the outer faces of the second slant wall 317 andthe second vertical wall 318 of the second side wall part and the cover330 of the bobbin 300.

In this manner, the plurality of lamination sheets 110 are radiallystacked to make a cylindrical form on the basis of the bobbin 300.

The end portion of the extended part 112 and the end portion of the passpart 111 positioned at both sides of the bottom part 311 of the bobbinmakes a pole part 113 which forms a pole, and the distance between thepole parts 113 makes an interpole distance Lb1. The interpole distanceLb1 is equivalent to the width of the bottom part 311 of the bobbin.

The length Lm1 of the permanent magnet 420 of the mover 400 isequivalent to the sum of the width Lb1 of the bottom part 311 of thebobbin, that is the distance between the pole parts 113, and the lengthLp1 of one pole part 113.

The inner core 200 is formed as a cylindrical stacked body thatrectangular thin lamination sheets 210 having the length equivalent tothe length of the outer core 100 are radially stacked to make acylindrical form.

FIG. 8 is a flow chart of a method for fabricating the bobbin of areciprocating motor in accordance with the preferred embodiment of thepresent invention.

As shown in FIG. 8, the bobbin body 310 having the first side wall part312 and the second side wall part 313 which are respectively extended toa predetermined height having a slant portion at both sides of thering-shaped bottom part 311 of a predetermined width and form a spacetherein is first molded by using a resin.

And then, the winding coil 320 is fabricated by winding a coil for manytimes in the space formed inside the bobbin body 310. The winding coil320 is positioned at the inner space formed by the bottom part 311 andthe first and the second side wall parts 312 and 313 of the bobbin body310.

The cover 330 is secondly molded to the bobbin body 310 to cover thewinding coil 320. The cover 330 is preferably made of a resin.

The operational effects of the bobbin of the reciprocating motor and itsfabrication method will now be described.

First, in the reciprocating motor, when a current flows to the windingcoil 320, a flux is generated around the winding coil 320 due to thecurrent flowing to the winding coil 320. The flux flows forming a closedloop along the outer core 100 and the inner core 200 constituting thestator (S).

The interaction between the flux according to the current flowing alongthe coil 320 and the flux according to the permanent magnet 420constituting the mover 400 makes the permanent magnet 420 to move in theaxial direction.

When the direction of the current flowing to the winding coil 320 ischanged, the direction of the flux formed at the outer core 100 and theinner core 200 is accordingly changed, and thus, the permanent magnet420 is moved in the opposite direction.

When the current is supplied to the permanent magnet 420 by changing itsdirection by turns, the permanent magnet 420 is moved linearly andreciprocally between the outer core 100 and the inner core 200.Accordingly, the mover 40 has a linear reciprocal driving force. Thisprocess is the same as described above.

In the bobbin 300 of the reciprocating motor, the winding coil 320 isformed as a coil is wound for many times therein. Thus, the winding coil320 can be easily fabricated. In addition, the plurality of laminationsheets 110 are stacked on the bobbin 300 having the winding coil 320therein, to thereby fabricate the outer core 100, so that the operationof stacking the lamination sheets 110 is easily performed. Moreover, thedimension of the outer core 100, that is, the stacked body, is accurateand the dimension management is facilitated.

The slant wall is formed at the first and the second side wall parts 312and 313 of the bobbin body 310, and as the lamination sheets 110 arestacked as being contacts with the slant wall to form the outer core100, the distance between the pole parts 113 of the outer core, that is,the interpole distance Lb1, is reduced, leading to reduction to thelength Lm1 of the permanent magnet 420 constituting the mover 400.

Furthermore, since the step faces (F) are formed at the first and thesecond side wall parts 312 and 313 of the bobbin, the coil is closelywound without being pushed. Thus, the number of winding of the windingcoil wound inside the bobbin 300 can be relatively increased.

The bobbin 300 includes the bobbin body 310 and the cover 330, the firstcombining part 314 is formed at the bobbin body 310, and the secondcombining part 331 is formed at the cover 330. And then, as the firstand the second combining parts 314 and 331 are combined, the cover 330is combined to the bobbin body 310. Thus, the parts are simply combinedand their combination states are firm.

In addition, since the protrusive louver 319 is formed at the outer faceof the bobbin body 310, the stacked body is firmly stacked at the bobbin300, that is, the outer core 100 and the bobbin are tightly adhered, sothat a vibration noise possibly caused due to shaking between the bobbin300 and the stacked body during an operation of the motor can beprevented.

Meanwhile, as for the method for fabricating the bobbin of thereciprocating motor, after the bobbin body 310 constituting the bobbin300 is molded by resin, on which the coil is wound for many times, andthen the bobbin body 310 and the cover 330 are molded to integrate them.Thus, the production process is simple and the combination state ismaintained firm.

As so far described, the bobbin of the reciprocating motor and itsfabrication method have many advantages.

For example, first, the winding coil and the outer core can be easilyfabricated.

Secondly, as the length of the permanent magnet constituting the moveris reduced, the unit cost for a production of a motor can be reduced aswell as heightening its productivity.

It will be apparent to those skilled in the art that variousmodifications and variations can be made in the plasma polymerization onthe surface of the material of the present invention without departingfrom the spirit or scope of the invention. Thus, it is intended that thepresent invention cover modifications and variations of this inventionprovided they come within the scope of the appended claims and theirequivalents.

1. A bobbin of a reciprocating motor comprising: a bobbin body having afirst side wall part and a second wall part which are respectivelyextended to a predetermined height to have a tilt portion at both sidesof a ring-shaped bottom of a predetermined width to thereby form apredetermined space therein; a winding coil formed by winding a coil forseveral times at a space formed inside the bobbin body; and a covercombined with the bobbin body to cover the winding coil.
 2. The bobbinof claim 1, wherein a first combining part is formed at the end faces ofthe first and the second side wall parts of the bobbin body and a secondcombining part is formed at the inner face of the cover and combinedwith the first combining part.
 3. The bobbin of claim 2, wherein thefirst and the second combining parts are concavo-convex for mutualcombination.
 4. The bobbin of claim 1, wherein a plurality of recessesare formed at end faces of the first and the second side wall parts ofthe bobbin body and a plurality of protrusions are formed to be combinedwith the recesses at the lower surface of the cover so that theprotrusions of the cover can be combined with the recesses of the bobbinbody.
 5. The bobbin of claim 1, wherein the first side wall partincludes a first slant wall having a predetermined thickness extendedlyformed to having a predetermined slope angle to a bottom part at oneside of the bottom part, and a first vertical wall extendedly formedfrom the first slant wall in the vertical direction to the bottom part,and the second side wall part includes a second slant wall having apredetermined thickness extendedly formed to having a predeterminedslope angle to the bottom part at the other side of the bottom part, anda second vertical wall extendedly formed from the second slant wall inthe vertical direction to the bottom part.
 6. The bobbin of claim 5,wherein a plurality of step faces are formed at the inner faces of thefirst slant wall and the second slant wall.
 7. The bobbin of claim 1,wherein the first side wall part includes a first slant step wall formedin a stairway form and having a predetermined thickness at one side ofthe bottom part and a first vertical wall extendedly formed from thefirst slant step wall in the vertical direction to the bottom part, andthe second side wall part includes a second slant step wall formed in astairway form and having a predetermined thickness at one side of thebottom part and a second vertical wall extendedly formed from the firstslant step wall in the vertical direction to the bottom part.
 8. Thebobbin of claim 1, wherein a protrusive louver is formed at the whole ora partial outer face of the first wide wall and the second side wallpart, so as to be closely adhered to a motor core when combined with themotor core.
 9. The bobbin of claim 1, wherein the bobbin body and thecover are integrally shaped by molding.
 10. A method for fabricating abobbin of a reciprocating motor comprising the steps of: first-moldingthe bobbin body having the first side wall part and the second side wallpart which form a predetermined space therein by being extended to apredetermined height to have a tilt portion at both sides of thering-shaped bottom of a predetermined width; fabricating a winding coilby winding a coil for plural times at the space formed inside the bobbinbody; and second-molding the cover combined with the bobbin body tocover the winding coil.
 11. A bobbin of a reciprocating motorcomprising: a bobbin body manufactured by molding, the bobbin bodyhaving a first side wall part and a second wall part which arerespectively extended to a predetermined height to have a tilt portionat both sides of a bottom of a predetermined width to thereby form apredetermined space therein; a winding coil formed by winding a coil forseveral times at a space formed inside the bobbin body; and a covermanufactured by molding and combined with the bobbin body to cover thewinding coil.